The Bush administration yesterday dismissed Iraq's agreement to begin destroying prohibited missiles as a meaningless gesture designed to deceive the world about its intentions to disarm, and said it would have no bearing on U.S. determination to force a U.N. Security Council decision on going to war.

But even as the administration was insisting that nothing short of total, immediate disarmament would be enough to avoid the use of military force, chief U.N. inspector Hans Blix was preparing to propose a series of tasks by which Iraq could gradually prove its claim that it has no weapons of mass destruction.

In a report to be distributed to council members Monday, Blix lists certain aspects of Iraqi cooperation but concludes that disarmament in a tangible sense has not occurred, U.N. officials said. By offering the list of outstanding tasks, however, Blix presumes that Iraq will be given more time and invites the council to set a deadline.

Although the United States and Britain, its main council ally, are likely to be pleased with Blix's criticism of Iraq's failure to produce documentary and physical evidence of its claims, Washington is trying to head off any suggestion that inspections should be allowed to continue. Both France and Canada, which is not a council member, have already made separate deadline proposals. The French proposal, which is backed by Germany, Russia and China, does not set a date.

The Canadian initiative calls for the tasks to be completed by the end of March. The initiative is favored by at least some of the half-dozen council members that dislike the lack of definition in the French proposal but oppose U.S. insistence that the time has come for a war decision.

Blix believes that it would take until the beginning of June to make a final determination of whether Iraq had complied with the tasks he has outlined, said one council member who spoke to the chief inspector. Blix will deliver an oral report to the council next Friday.

President Bush said late last month that the determination must be made in "weeks, not months." The administration has tried to force the issue by putting forth a new council resolution declaring that Iraq has already violated U.N. disarmament demands. In introducing the resolution last Monday, the United States and Britain made clear that they consider it authorization for war. Administration officials have said they plan to call for a vote sometime during the week of March 10.

One of the tasks on Blix's list is destruction of Iraq's Al Samoud-2 missiles, and all associated components, whose range exceeds U.N. limits. Iraq's agreement to do so, beginning today, has already given aid and comfort to the council majority opposing the U.S. resolution.

Administration spokesmen came out in force yesterday to deride the Iraqi agreement as no more than Baghdad's latest propaganda ploy. Coordinated statements from the White House and the State and Defense departments picked up a theme Bush launched last week when he called the missiles the "tip of the iceberg" of Iraq's prohibited weaponry and predicted that Baghdad would try to seduce antiwar factions by agreeing to their destruction.

"This is exactly what's been going on for years," Defense Secretary Donald H. Rumsfeld said. "They refuse to cooperate; don't cooperate; drag it out; wait till someone finally nails them with one little piece of the whole puzzle and refuse to do anything about it; and then finally, when they see the pressure building, say 'Well, maybe we'll do some of that.' So I don't see any change in the pattern at all." Inspectors plan to meet with the Iraqis in Baghdad this morning to work out a schedule for missile destruction.

Officials said Blix is aware that whatever he says Friday will fuel both sides of the increasingly rancorous council debate.

In seeking more Iraqi cooperation, Blix is expected to ask Baghdad to declare its inventory of underground facilities, where U.S. officials have repeatedly said missiles and laboratories for producing biological and chemical weapons are located. He will also ask Iraq to come up with a system by which inspectors, using roadblocks and helicopters, could monitor highways in search of mobile weapons laboratories the United States has alleged it has.

Blix has told colleagues that Iraq is "actively cooperating" in some disarmament areas at the moment; "for example, frantically digging in an area where it claims biological weapons were destroyed," a U.N. official said. Although Baghdad has claimed that it destroyed all its chemical and biological weapons stocks years ago, it has failed to produce U.N.-required documentary or physical proof.

Staff writer Colum Lynch at the United Nations contributed to this report.